net energy and clean water from wastewater · 27/1/2010 · objectives that need to be achived to...

Net Energy and CleanWater from Wastewater

ARPA‐E Potential FOA Mark A. Shannon January 27, 2010

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ARPA‐E Water‐Energy from Wastewater Program

The “Box” For Energy‐Water from Wastewater

ARPA‐E Workshop Structure

Case for Water‐Energy from Wastewater

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Workshop Context input might upcoming impactful

complements existing DOE, EPA, accelerat promising pment ladder,

piloting

Workshop on“Energy & Clean Water From Wastewater”Workshop Objectives 1. Obtain feedback from U.S. researchers, cognizant companies, and water associations

as to the objectives and metrics to achieve net energy output and clean usable water from municipal and industrial wastewaters.

2. Identify promising technical directions with the potential to radically improve net energy exaction and clean water from wastewater, and identify key technical barriers.

3. Identify potential performers, and discuss teaming for system integration, and piloting for real wastewaters.

Workshop ContextProvide as to how ARPA‐E structure an FOA so that anProvideinput as to how ARPA‐Emight structure anupcoming FOA so that animpactful2‐Phase 3 year program is created that and Federal2‐Phase 3 year program is created thatcomplements existing DOE, EPA, and Federal research programs and es ideas up the develo so thatresearch programs andaccelerat espromising ideas up the development ladder, so that a stage in select small towns can start after 3 years.apiloting stage in select small towns can start after 3 years. Format Focused breakout sessions with reports to the group ‐ Two tracks: Science & Techology and Implementaion & Translation

‐ Four breakouts in each track. 15 minute “report out” by chair of each session

Joint Combined Methods Session 3

Overarching Goal of Program 1. Recover usable energy contained in wastewater to help

renewably supply some of U.S. Energy needs. 2. Recover usable clean water from wastewater to:

1. Reduce embedded energy cost needed to supply new water, 2. Effectively increase water available for human use.

3. Reduce greenhouse emissions emanating from: 1. Wastewater hydrocarbons, 2. Energy used to treat and discharge wastewater, 3. Energy used to transport and treat supply waters.

4. Increase American Competitiveness: 1. Translating advances made in program to U.S. businesses 2. Implementing and adopting new technologies by utilities,

companies, govermental units, and other end users.

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The Case For Water

• Will have large growth in demand on average, but many localities will see huge increases.

• Conservation alone cannot meet demand…not even rationing by 50% or more (at most a 2x increase).

• Need something that can increase effective supplies by many factors (3x, 4x, up to 100x)

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Depletion of Groundwaters & Loss of Ice-Snowpack Storage

Light blue: Standard aquifers Dark blue: Rivers and lakes Green: Aluvial and glacial aquifers Red: Stressed aquifers Yellow: Impacted aquifers White: Declining snowpack storage

U.S. Department of the Interior http://www.nationalatlas.gov WaterCAMPWS http://www.watercampws.org

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http://www.nationalatlas.gov

http://www.watercampws.org

Salting Issues Darkened: Regions with excess salting

1,400-km2 study area in western Fresno County CA experiencing 0.5 Mton/yr salting rate since 1945 with an average salt concentration now of 1,150 mg/liter in the aquifer beneath the Corcoran clay [Schoups et al., PNAS 102:43, p. 15352-15356 (2005)]

Salting from

seawater intrusion,

ag practices, industry, &

water treatment

itself

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350

400

450

500

2020 2025 2030 2035 2040

Water Use With Growth in Population

0

50

100

150

200

250

300

2000 2005 2010 2015 Year

population (millions) (1% growth)

conservation (4% yearly decline)

same use as now

projected (4% yearly increase)

Population Data form US Census Bureau The Blueprint 2030 forecast share of the revised United States population growth forecast from 2000 to 2030 was 1.14%

Growth rate in consumption assumed to

be ~60% of population growth after 15%

elasticity…it “compounds” with time.

% Increase

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2030 Projected % Increase (since 2000) Averages don’t tell the real story: Growth problems will be local.

Population data and projections from U.S. Census Bureau http://www.census.gov/population/www/projections/stproj.html http://www.census.gov/popest/datasets.html

Water Use Data from USGS (http://web1.er.usgs.gov/NAWQAMapTheme/index.jsp) Projections for water use based on Texas Water Use 60 yr projections (http://www.twdb.state.tx.us/publications/reports/State_Water_Plan/2007/2007StateWaterPl an/2007StateWaterPlan.htm)

% Increase 0‐25 25‐50 51‐100 101‐300 301‐1000

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Why Water Recovery?

• Only 10 to 30% of water actually consumed (70 to 90% returned) in municipal and industrial systems. Reuse can effectively increase supplies by 3.3x (70%) up to 100x (99%).

• Compare to conservation (50% reduction gives a 2x gain). Conservation of consumed (evaporated) water when combined with reuse can get to 90+%

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What is “Clean Usable Water”• We need water that can be used for most all uses. It has

to be safe (pathogen and toxic compound free), low in dissolved solids (salts) and suspended solids (solids). Does it need to be clean enough for intimate human contact?

• Currently reclaimed water ~ costs near desalination. If non‐potable water, separate distribution system needed to realize gain.

• Can recharge ground water (as in Orange county & coming to San Diego). There, the water undergoes tertiary treatment, followed by RO…at a cost more than $1/m3.

• But how to make it affordable? Instead of destroying energy content and using chemicals, extract energy and nutriments, which also equate to energy.

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Why Municipal Wastewater?• Municipal – Mixed suspended and dissolved solids, ranging from 100 ppm for combined sewers to 500 ppm for dedicated sanitary. How small a system can we go to recover energy and water?

• Industrial – Pharma, petrochemical, food, agribusiness,forest products, ranging from 1,000 to 100,000 ppm.

• Agriculture – Crop waste, cattle & swine (total solids is 7,210 mg/l, total volatile solid is 5122 mg/l), poultry wastes (total solids of 8,300 mg/l, and volatile solids in the amount of5,400 mg/l).

Strength of Waste in ppm

{mg/liter, g/m3}

Energy Content {Joule/liter, kJ/m3}

1 25.6

10 256

100 2,560

1,000 25,600

10,000 256,000

100,000 2.56 106

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Current Treatment & Energy Method• Energy and water recovery in an secondary treatment plant. Many points of energy inputs and losses.

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Current Advanced Clean Water Reuse• Water produced by the Groundwater Replenishment System for

the Orange County Water District first comes from the effluent of a primary and secondary wastewater treatment plant. It is then purified using state‐of‐the‐art microfiltration, reverse osmosis, ultraviolet light and hydrogen peroxide treatment techniques, before injection into the ground. Each uses relatively high‐energy.

Mechanical Air Pumping Reverse Osmosis Work In for Aerobic Micro‐

Digestion Filtratio Primary n

Secondary Concentrat e Rejection

50%

Sludge Removal Ground UV Irradiation H2O2 Injection

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Achieving Net Energy & Clean Water Output• How we draw the control volume matters. If one only draws the

volume around the sludge out, one can show net energy generated. But if one accounts for all inputs and outputs from the sourcewater to the output, it is much harder.

All Work & heat In All Work In All Work In

Wastewater Mechanical In Stirring & Fluid Air Pumping Reverse Osmosis

Shearing Work for Aerobic Micro‐Digestion Filtration

Primary

Secondary Concentrate Rejection

50% UV Irradiation H2O2

All All Materials Out: All Electrical All Chemical

Energy Dewatering,Hauling, All Water Out Energy In Energy In

Out Burning 17

Balances• Want to account for all inputs and outputs from the processes

developed: Energy, chemical, input and output streams (i.e. wastewater in (chemical and thermal), clean and discharge water out (chemical and thermal), sludge out (chemical and thermal), chemicals in and out, mechanical and electrical work in and out). – We need to put an energy value on all inputs and outputs! Nothing gets a

free ride (i.e. ozone, chlorine, ammonia, HCl, NaOH, nutrients, sludge to landfill,…) . We need total lifecycle analysis on sustainablity.

• Want to account for all change in greenhouse gases from the processes developed (i.e. amount of organics remaining in sludge discharged, savings from converting to usable net energy, chemicals used or saved, nutrients recovered, embedded enegy avoided, electrical to primary energy multiplier, quality of discharged water) – We need to put a GHG value on all processes of the system. Need the total

cycle analysis to determine sustabability of the technology adopted. 18

Problem with Recovering Energy: Water! • Water content does not add to energy

– Need to extract energy from multiphase waste at cost perkW‐hr that is competitive with other sources of energy.

• Dewatering waste takes energy – Taking it all the way to dry mass takes a lot of energy (latent heat of evaporation ~2,260 kJ/kg of water content)

• Solids and volatiles complicate dewatering…different methods needed. – Settling (cheap, but slow and limited in performance), flocculation (leaves chemical residual), spinning (capital intensive), vacuum stripping (energy‐capital intensive), evaporation (very energy intensive)

– Clear liquor and/or mineral residuals still needsprocessing. 19

More Problems to Overcome• Heating of lots of water takes lots of energy

– Higher temperatures typically mean higher kinetics and higher yields, but higher quality heat is needed, and thermal management to control direct and available work losses.

• Solids contain clays, hard salts, sulfur compounds, etc. – Ash and minerals reduce conversion (thermal, chemical, and

biological) efficiencies. Minerals retained and foul. Foulants interfere with membrane separations, and catalyst processes.

• Wastewater highly variable – Large variations in water content, temperature, pH, protein,

fats, salts, & carbohydrates. Contains toxic industrial compounds, household cleaners, oils, tars, and everything that goes down a drain, as well as antibiotics that can be retained or kill beneficial microbes. Variations are temporal and seasonal.

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More Problems to Overcome• Pathogens in abundance

– Even non‐potable water needs to be pathogen‐free to be used in most applications, even if not for intimate human contact. Most dangerous are viruses, which can pass through most normal membranes. Some can survive temperatures > 100°C.

• Small toxic compounds pass through many processes – Small molecules pass through membranes and as volatiles. Many logs (up to 6) reduction needed.

• Long retention times typically needed – Slow rates for conversion typically mean large, expensive systems are needed. Capital intensive.

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Workshop Structure1. Science and Technology Track

In this track, we want to try establish the metrics that can possibly be achived to extract energy and clean water from municipal (low strength) wastewater. What are the scientifically possible metrics w.r.t. amounts and cost, and what are the technologies we should invest in that might achieve those metrics? 1.Clean water from wastewater

1. Metrics and technologies

2.Energy (nutrients) from wastewater 1. Metrics and technologies

This track is to inform ARPA‐E as to what S&T to invest in that can revolutionize simultaneously obtain clean water and energy (nutrients/minerals) from wastewater.

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Workshop Structure2. Implemention and Translation Track

In this track, we want to try establish the metrics and objectives that need to be achived to extract energy and clean water from municipal (low strength) wastewater in order for the technologies to be considered for adoption.

1.Energy and clean water from wastewater 1. Metrics and objectives

2.Translation in practice: Metrics, outcomes, piloting, barriers and solutions

1. Barriers and solutions for implementation

This track is to inform ARPA‐E as to what is needed for the S&T that might be invested in so that the technology can be adopted and implemented, and translated into practice, while increasing American Competitivness.

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Science and Technology Track Morning

Clean Water from Wastewater‐ Group 1Senate Ballroom Salon CJim Smith, US EPA NRML

Group 1: Science and technological challenges to obtaining clean water from wastewater with more than an order of magnitude better performance than current technologies

Clean Water from Wastewater‐ Group 2Senate Ballroom Salon BBenito Mariñas, University of Illinois

Group 2: Emerging methods of deriving clean water from wastewater with associated metrics

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Science and Technology Track Afternoon

Net Energy from Wastewater: Science and Technology Needed, with Associated Metrics‐ Group 1

Senate Ballroom Salon C Mohamed Dahab, University of Nebraska

Group 1: Science and technological challenges to obtaining energy from wastewater with more than an order of magnitude better performance than current technologies

Net Energy from Wastewater: Science and Technology Needed, with Associated Metrics‐ Group 2

Senate Ballroom Salon B William Horak, Brookhwaven National Laboratory

Group 2: Emerging methods of deriving energy from wastewater with associated metrics

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Implementation and Translation TrackMorning

Energy and Clean Water from Wastewater‐ Group 1 Senate Ballroom Salon A Eugenio Giraldo, American Water

Group 1: Quality and costs needed for water to be reused from wastewater

Energy and Clean Water from Wastewater‐ Group 2 Gallery Room Sudhir Murthy, DC WASA

Group 2: Barriers (Infrastructure, codes, permits, and requirements) and incentives needed

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Implementation and Translation Track Afternoon

Translation into Practice: Metrics, Outcomes, Piloting, Barriers and Solutions‐ Group 1

Senate Ballroom Salon A Cat Shrier, Watercat Consulting Shadid Chaudhry, California Energy Commission

Group 1: Metrics and outcomes needed for pilot demonstrations and implementation of technologies developed in program

Translation into Practice: Metrics, Outcomes, Piloting, Barriers and Solutions‐ Group 2

Gallery Room Joe Zuback, Global Water Advisors

Group 2: Barriers to adoption and solutions needed for translation of technologies into practice

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net energy and clean water from wastewater · 27/1/2010 · objectives that need to be achived to...

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